1. Field of the Invention
The present invention relates to an internet fax system, a transmission result ascertaining apparatus for internet fax, a method of running an internet fax network, and a message format for an internet fax.
2. Background of the Related Art
When fax data are transferred using the internet network, reports of transmission result and transmission time of the transferred data as are required for securing reliance of the transmission.
The fax transmission is generally achieved through Public Switched Telephone Network(hereinafter abbreviated PSTN) or Internet Network.
Protocols for transmitting the fax data through the internet network, which are called FoIP(FAX over Internet Protocol), include a store and forward transmission method of transmitting fax files having been stored therein and a real-time transmission method of transmitting the fax files immediately.
Generally, the fax files are tried to transmit by the real-time transmission method first. If this transmission fails, the store and forward transmissions method are executed automatically for the transmission.
In toll fax or international fax transmission, FoIP is different from international fax transmission service, which charges international call fees, using PSTN and fax transmission network.
FoIP is a sort of an internet service technology which enables to reduce greatly the cost for transmission/receive of the fax data globally using the international internet network. Moreover, by evading the PSTN path, FoIP enables to realize additional functions such as transmission security guarantee, routing path of minimum price, dissolution of call stand-by, on-line call report, browser for fax/e-mail. Besides, various marketing points of FoIP can win over lots of customers.
As mentioned in the above explanation, gateways connected to the internet network are essential to realize FoIP. Such gateways are generally installed inside personal computers.
FIG. 1 shows a diagram of a protocol structure of gateways.
Referring to FIG. 1, the real-time transmission method transmits fax data using IFP(internet fax protocol), TCP/IP or UDP/IP protocol prescribed in T.38, while the store-forward transmission method transmits the fax data using SMTP(simple mail transport protocol) prescribed in T.37.
FIG. 2 shows a diagram for explaining schematically a process of fax data transmission through the internet network.
Referring to FIG. 2, analog data produced by an inner scanner of a transmission party fax are converted into digital data of 9.6 kbps so s to be sent to a modem.
Converting the digital data into analog data again, the modem sends the analog data to a gateway of the transmission party through PSTN.
The gateway of the transmission party carries out demodulation installed inside for transmitting the fax analog data through the internet network, whereby the analog data are converted into packet data. Then, the packet data are transmitted to the other gateway of the receive party through the internet network by 9.6 kbps.
The gateway of the receive party remodulates the fax packet data, which have been transmitted through the internet network, by DSP installed inside, whereby the fax packet data are converted into analog data so as to be transmitted to a receive party fax through PSTN. In the modem installed in the receive party fax, the received analog data are converted into digital data again to be sent to an inner print. The inner printer installed in the fax outputs contents corresponding to the digital data.
FIG. 3 shows a diagram for explaining the store-forward transmission method. Referring to FIG. 3, the transmission party fax transmits the fax data to the gateway of the transmission party using PSTN with T.30 protocol.
The gateway of the transmission party stores the fax data received from the transmission party fax in inner memory first, and then transmits the stored fax data to the gateway of the receive party through the internet network.
In this instance, SMTP(simple mail transport protocol) is used for transmitting the fax data by the store and forward transmission method through the internet network. In this case, the transmitted fax data are encoded as MIME(multipurpose internet mail extension) by using TIFF-F(tagged image file format-class F).
Then, the gateway of the receive party completes the fax data transmission process using the internet network by transmitting the fax data received through the internet network back to the receive party fax through PSTN.
FIG. 4 shows a diagram for explaining the real-time transmission method. Referring to FIG. 4, the transmission party fax transmits the fax data to the gateway of the transmission party through PSTN by T.30 protocol.
The gateway of the transmission party converts T.30 protocol into T.38 protocol and then transmits the fax data to the gateway of the receive party using the internet network.
In this case, in order to transmit the fax data through the internet network by the real-time transmission method, fax data are transmitted by IFP(internet fax protocol) and TCP/IP, or IFP and UDP/IP prescribed in T.38.
Then, the gateway of the receive party completes the fax data transmission process using the internet network by converting the T.38 protocol into the T.30 protocol and then by transmitting the fax data received to the receive party fax through PSTN.
As mentioned in the above explanation, the gateways according to the related art fail to ascertain whether the transmitted fax data are transferred to the gateway of the receive party correctly as well as the transmission time of the transmitted fax data when the fax data are being transmitted/received through the internet network.
Unfortunately, the related art provides poor reliance of he fax data transmission.